Flywheel assemblies are typically coupled to an armature shaft of an electric motor to maintain rotational speed of the motor by virtue of the inertia of the flywheel. In addition, combination assemblies, including a flywheel, a fan to cool the electric motor, and a pulley to transfer torque from the electric motor to other components, can be coupled to a shaft to perform these multiple functions.
There are currently several known methods for attaching a flywheel to a shaft of an electric motor. These methods include a slip fit arrangement, illustrated in FIG. 1, in which a bore of a flywheel 10 includes a threaded portion 11 and an end 20 of a shaft 21 of an electric motor 15 includes complementary threads. The flywheel 10 is coupled to the shaft 21 by screwing the flywheel onto the shaft. Another method is a keyed shaft arrangement, as shown in FIG. 2, in which a keyway 112 is cut through a hub 111 of the flywheel 110 and a complementary key 113 is provided in the shaft 120 of the electric motor 115 to hold the flywheel 110 in position relative to the shaft 120. A hole 114 for a set screw (not shown) can also be provided to secure the flywheel 110 to the shaft 120.
However, the current methods for coupling a flywheel to a shaft of an electric motor can be disadvantageous for several reasons. The methods require added coupling hardware such as bolts and set screws, or require keyways to be cut in the flywheel and the shaft, both adding to manufacturing time and cost. In addition, the methods rely on a slip fit between the flywheel and the shaft, which may result in the flywheel becoming unbalanced with respect to the shaft, resulting in higher noise and oscillations.
Accordingly, there is a need for a system for coupling a flywheel assembly to a shaft of an electric motor, the system being simple and reliable.